Lactate Threshold Question

I'm 40 years old, 5'8", 148 lbs, been biking on and off for 15 years at various levels of commitment, never all that serious.

I just got the results of my blood lactate test and I was surprised to see how low my Lactate Threshold is.
For the first ten months of 2006 my riding consisted of doing 5 or 6 spin classes a week at the gym and riding the entire time high in the anaerobic zone (or riding laps in Central Park at a similar pace), >160 bpm.

About two months ago I decided to try and formulate a real road bike training plan, got Friel's Training Bible and realized I was doing absolutely no riding below threshold. So for the last two months that's what I've been doing most of the time (about 10-12 hours week, 6 of which are outdoors on the the bike, the rest indoors).

My max heart rate is 189, but the results of the test (yes, they took blood) yielded my LT at 156. My power output at threshold was respectable, but I thought the actual heart rate at threshold would be higher than 156. Could this low number be due to ten months of almost exclusively training way above threshold?

"Lactate Threshold" in cycling terms is actually a combination of true "LT" and VO2-max HR. Real LT is simply a muscular force. When combined in cycling, gearing comes into play. Repeat your LT tests at 90rpm, 95rpms, 100rpms, 105rpms at the same speed and you'll find that the "LT-HR" will vary based upon gearing.

Typically, LT-HR will be higher when using lower gears and spinning at 100rpms. Power-output at LT will tend to be a little higher as well, depending upon your neuro-muscular coordination at that RPM. At lower-RPMs, LT-HR will be lower along with lower power-output due to the higher forces needed on the pedal.

The trick is to balance your muscles vs. your heart. If your legs hurt but lungs/heart feel fine, then use lower gear and spin more. If your lungs/heart hurt, but legs feel fine, then use a bigger gear and push harder.

I think you were training just fine. Your LT is 84% of your max HR, that's within range.

With enough time, you probably can raise that LT to 88% or so. But it can take years to get it to that point.

There's also the possibility that the LT blood test isn't that valuable. Go out and do a functional test (see the sticky article in this forum). If you've been riding at a higher intensity than your measured LT, I suspect your actual threshold is higher.

riding the entire time high in the anaerobic zone (or riding laps in Central Park at a similar pace), >160 bpm......My max heart rate is 189

Unless your spin classes lasted less than 60 seconds there is no way you spent the entire time high in the anaerobic zone. If your max HR is 189, then 160 bpm is just aerobic. High anaerobic would have been 180bpm+

Unless your spin classes lasted less than 60 seconds there is no way you spent the entire time high in the anaerobic zone. If your max HR is 189, then 160 bpm is just aerobic. High anaerobic would have been 180bpm+

"Lactate Threshold" in cycling terms is actually a combination of true "LT" and VO2-max HR. Real LT is simply a muscular force.

Lactate threshold is properly defined as an exercise intensity usually interms of power or VO2. It is never a force. For example, my legs can exert a force of 90 lbs virtually indefinitly, yet I reach my functional threshold (higher than LT) at 250W and a force of about 35 lbs.

wait, do you ride according to these zones? i have basically the same max HR that you do, but i have a resting HR of 55. still, my prescribed zone 2 (where i spend most of my time these days) is lower than what you listed. perhaps this is the difference between running and cycling??

Lactate threshold is properly defined as an exercise intensity usually interms of power or VO2. It is never a force. For example, my legs can exert a force of 90 lbs virtually indefinitly, yet I reach my functional threshold (higher than LT) at 250W and a force of about 35 lbs.

Well, it's really a measurement of blood-lactate levels. LT is defined as the "knee point" on the molality graph where blood-lactate it takes a sharp turn upwards and can't be cleared fast enough to maintain equilibrium.

In your example, if you were producing 250w @ 90rpms, you can exert the same force at 5% higher RPMs (on gear lower on straight-block) and probably get 5% more power. Your HR will increase, however, if it was below VO2-max, then you won't be overdriving the lungs.

Although in your case, your legs might be stronger than your cardio system, so you might actually have higher power-output at lower-RPMs.

The more effective test would be to measure blood-lactate at differnet RPMs with constant power-output. So at the same 250w, measure blood-lactate at 90-110rpms in 5-rpm increments. You'll find that lactate-levels will vary. There will be one rrpm in that range that yields lower lactate than the others, a valley of sorts if you graph it. This is where your muscular-efficiency is best.

Well, it's really a measurement of blood-lactate levels. LT is defined as the "knee point" on the molality graph where blood-lactate it takes a sharp turn upwards and can't be cleared fast enough to maintain equilibrium.

While the underlying concept for lactate threshold is the workload at which lactate can not be cleared as fast as it's produced, there are at least several dozen specific definitions of LT. These include a 1 mmol/l rise above baseline, 2 mmol/l above baseline, 2.5 mmol/l above baseline, 4 mmol/l absolute, etc. where baseline may be defined in terms of lactate concentration at rest or during light exercise. Not to mention the myriad ways to define the change in slope you refer to. Any report of LT values has to state precisely how LT is measured. So to say there is a single definition is truly misleading.

As to your examples with gear and cadence, the only protocols I trust to determine LT are independent of gearing. Using an ergometer, power is controlled and the rider is free to self-select the best cadence for them, because power is controlled independent of wheel speed, gearing is not a factor. Artificially imposing cadence or gear restrictions means that someone is no longer measuring LT, but something related to LT but confounded by the artificially imposed constraints.

The more effective test would be to measure blood-lactate at differnet RPMs with constant power-output. So at the same 250w, measure blood-lactate at 90-110rpms in 5-rpm increments. You'll find that lactate-levels will vary. There will be one rrpm in that range that yields lower lactate than the others, a valley of sorts if you graph it. This is where your muscular-efficiency is best.

While this might be an interesting test, it has nothing to do with lactate threshold. The data would show lactate concentration as a function of rpm for the performed protocol, but I don't know what would be learned beyond that. It's not at all clear that performance (e.g., time to exhaustion) will be correlated with lactate concentration. So while I might learn that I produce a lactate concentrattion of 3.0 mmol/l at 90 rpm and 250W and 3..3 mmol/l at 80 rpm and 250 W. There's no reason to believe, based on this test, that my performance (however that's measured) will improve in going from 80 to 90 rpm.

The answer is don't worry about. You now have the HR number you need to set your workouts. Do a lot of steady state intervals (+/- 3 beats of LTHR) and you'll likely see your LTHR rise over the long haul.

But bottom line, its just a tool to set your training levels in a HR driven program. The actual number doesn't matter.

wait, do you ride according to these zones? i have basically the same max HR that you do, but i have a resting HR of 55. still, my prescribed zone 2 (where i spend most of my time these days) is lower than what you listed. perhaps this is the difference between running and cycling??

Yes. I do ride according to these zones....unless I just had a ton of coffee in which case it is all screwed up.

It has nothing to do with running. That was just the first website I found on the subject. There are many, many more that say the same thing. Your MAX HR will be higher while running, but the formulas are the same.

Here is a good calculator that shows the zones corrected for resting HR.

Yes. I do ride according to these zones....unless I just had a ton of coffee in which case it is all screwed up.

It has nothing to do with running. That was just the first website I found on the subject. There are many, many more that say the same thing. Your MAX HR will be higher while running, but the formulas are the same.

Here is a good calculator that shows the zones corrected for resting HR.

i guess you have to be careful with terminology. if i'm using friels heart rate zone chart, riding in zone 2 is putting me at less than 150bpm. riding at zone 2 in the example provided above, would actually put me in zone 3 (tempo ride) according to friel's charts.

Davey, we are the same height and similar weight (I'm a few pounds lighter), and I'm a year younger than you and female. I too follow Friel's training program. I had my VO2 max tested at the beginning on Dec. and my LTHR is 160, max heart rate 190. I rode a lot last year but really had to push to keep up with fellow riders. My results showed that I am very anaerobically strong, most likely due to aleays pushing hard while riding and 3 days a week of lifting. My tester prescribed that I do a lot of base miles keeping my heart rate between 153-160 to push my LT out farther so I last longer for racing. She recommmended retesting in a few months and guaranteed my LT would be higher if I did what she said. Good luck!

"The dictionary is the only place that success comes before work. Hard work is the price we must all pay for success." -Vince Lombardi

Davey, we are the same height and similar weight (I'm a few pounds lighter), and I'm a year younger than you and female. I too follow Friel's training program. I had my VO2 max tested at the beginning on Dec. and my LTHR is 160, max heart rate 190. I rode a lot last year but really had to push to keep up with fellow riders. My results showed that I am very anaerobically strong, most likely due to aleays pushing hard while riding and 3 days a week of lifting. My tester prescribed that I do a lot of base miles keeping my heart rate between 153-160 to push my LT out farther so I last longer for racing. She recommmended retesting in a few months and guaranteed my LT would be higher if I did what she said. Good luck!

the first time i did an LTHR test (doing the functional test on the road) i was around 156 or so. after my first season of racing i was about 165. now, i just did the same test a couple of weeks ago (right before starting base training) and i was at 168.

so, yeah, you can definitely improve it. and, as i've seen, by quite a bit too. i'd be curious to see how your LT has changed over the next few weeks\months.

the first time i did an LTHR test (doing the functional test on the road) i was around 156 or so. after my first season of racing i was about 165. now, i just did the same test a couple of weeks ago (right before starting base training) and i was at 168.

so, yeah, you can definitely improve it. and, as i've seen, by quite a bit too. i'd be curious to see how your LT has changed over the next few weeks\months.

She had me ride at a cadence that was comfortable, which was around 80. Per Danno's info, a higher cadence alone should cause an improvement. Like the OP, much of my training was anaerobic. I have been doing all my cardio at the 153-160 rate once warmed up so hopefully it proves true to push the LT up!

She also said that the race season may/should actually lower it again as much of the time you are anaerobic. I'll probably retest with her before racing starts April 15th just to see how much/if any improvement was made.

"The dictionary is the only place that success comes before work. Hard work is the price we must all pay for success." -Vince Lombardi